97 research outputs found
History of Wake County, North Carolina, with sketches of those who have most influenced its development, by Hope Summerell Chamberlin; pen and ink illustrations by the author.
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A survey of Fusarium species occurring in the grassland biome of South Africa
No full textAbstract: Please refer to full text to view abstract.Ph.D. (Botany and Plant Biotechnology
Fusarium spp. associated with soils from the Golden Gate Highlands National Park, South Africa.
No full textAbstract: Please refer to full text to view abstract.M.Sc. (Botany and Plant Biotechnology
The diversity of the genus Fusarium in soil from the Willem Pretorius Nature Reserve, South Africa
No full textM.Sc.Abstract: Please refer to full text to view abstract
A case for re-inventory of Australia’s plant pathogens
No full textAustralia has efficient and visible plant quarantine measures, which through various border controls and survey activities attempt to prevent the entry of unwanted pests and diseases. The ability to successfully perform this task relies heavily on determining what pathogens are present and established in Australia as well as those pathogens that are exotic and threatening. There are detailed checklists and databases of fungal plant pathogens in Australia, compiled, in part, from surveys over many years sponsored by Federal and State programmes. These checklists and databases are mostly specimen-based, which enables validation of records with reference herbarium specimens and sometimes associated cultures. Most of the identifications have been based on morphological examination. The use of molecular methods, particularly the analysis of DNA sequence data, has recently shown that several well-known and important plant pathogenic species are actually complexes of cryptic species. We provide examples of this in the important plant pathogenic genera Botryosphaeria and its anamorphs, Colletotrichum, Fusarium, Phomopsis / Diaporthe and Mycosphaerella and its anamorphs. The discovery of these cryptic species indicates that many of the fungal names in checklists need scrutiny. It is difficult, and often impossible, to extract DNA for sequence analysis from herbarium specimens in order to validate identifications that may now be considered suspect. This validation can only be done if specimens are recollected, re-isolated and subjected to DNA analysis. Where possible, herbarium specimens as well as living cultures are needed to support records. Accurate knowledge of the plant pathogens within Australia's borders is an essential prerequisite for the effective discharge of plant quarantine activities that will prevent or delay the arrival of unwanted plant pathogens
Myrtaceae, a cache of fungal biodiversity
No full textTwenty-six species of microfungi are treated, the majority of which are associated with leaf spots of Corymbia, Eucalyptus and Syzygium spp. (Myrtaceae). The treated species include three new genera, Bagadiella, Foliocryphia and Pseudoramichloridium, 20 new species and one new combination. Novelties on Eucalyptus include: Antennariella placitae, Bagadiella lunata, Cladoriella rubrigena, C. paleospora, Cyphellophora eucalypti, Elsinoë eucalypticola, Foliocryphia eucalypti, Leptoxyphium madagascariense, Neofabraea eucalypti, Polyscytalum algarvense, Quambalaria simpsonii, Selenophoma australiensis, Sphaceloma tectificae, Strelitziana australiensis and Zeloasperisporium eucalyptorum. Stylaspergillus synanamorphs are reported for two species of Parasympodiella, P. eucalypti sp. nov. and P. elongata, while Blastacervulus eucalypti, Minimedusa obcoronata and Sydowia eucalypti are described from culture. Furthermore, Penidiella corymbia and Pseudoramichloridium henryi are newly described on Corymbia, Pseudocercospora palleobrunnea on Syzygium and Rachicladosporium americanum on leaf litter. To facilitate species identification, as well as determine phylogenetic relationships, DNA sequence data were generated from the internal transcribed spacers (ITS1, 5.8S nrDNA, ITS2) and the 28S nrDNA (LSU) regions of all taxa studie
Taxonomy and phylogeny of the genus Mycosphaerella and its anamorphs
No full textHistorically plant pathogenic species of Mycosphaerella have been regarded as host-specific, though this hypothesys has proven difficult to test largely due to the inavailability of fungal cultures. During the course of the past 20 years a concerted effort has been made to collect these fungi, and devise methods to cultivate them. Based on subsequent DNA sequence analyses the majority of these species were revealed to be host-specific, though some were not, suggesting that no general rule can be applied. Furthermore, analysis of recent molecular data revealed Mycosphaerella to be poly- and paraphyletic. Teleomorph morphology was shown to be too narrowly defined in some cases, and again too widely in others. Mycosphaerella and Teratosphaeria as presently circumscribed represent numerous different genera, many of which can be recognised based on the morphology of their 30 odd associated anamorph genera. Although Mycosphaerella is generally accepted to represent one of the largest genera of ascomycetous fungi, these data suggest that this is incorrect, and that Mycosphaerella should be restricted to taxa linked to Ramularia anamorphs. Furthermore, other anamorph form genera with Mycosphaerella-like teleomorphs appear to represent genera in their own right
Co-occurring species of Teratosphaeria on Eucalyptus
No full textA common leaf spot disease occurring on Eucalyptus cladocalyx and E. lehmannii in the Western Cape Province of South Africa is known from literature to be caused by the fungus Coniothyrium ovatum, which is a pathogen native to several eucalypts in Australia. Recent collections have shown that Australian material identified as C. ovatum is morphologically and phylogenetically distinct from the South African specimens, and that all these taxa would be better accommodated in the genus Teratosphaeria. South African specimens previously identified as C. ovatum were found to represent two species that co-occur in the same leaves and even spots and are described here as T. juvenalis and T. verrucosa. Furthermore, a fresh collection of T. ovata from E. phoenicea in Australia, is distinguished morphologically and phylogenetically from similar, newly described taxa such as T. veloci on E. miniata, and Readeriella dimorpha, which is also placed in Teratosphaeria. Although these leaf pathogens appear to be of minor economic importance, they are morphologically similar to two serious eucalypt canker pathogens, namely T. gauchensis and T. zuluensis, which predominantly cause stem cankers, but could also be found occurring in leaf spots on their own, or in association with some of the other species treated here. Further research is, therefore, required to develop molecular detection techniques for these taxa to enable researchers to rapidly distinguish the minor pathogens from the more serious quarantine pathogens that co-occur on leave
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